Does the Addition of Neostigmine to Intrathecal Bupivacaine-Fentanyl provide Significant Haemodynamic Stability in Patients Undergoing Surgery under Spinal Anaesthesia?

Abstract

Background: Hypotension is a common complication of spinal anaesthesia. Neostigmine, an anticholinesterase, when given intrathecally has been shown to counteract the hypotensive effects of local anesthetic thereby providing haemodynamic stability during spinal anaesthesia. The aim of this study was to test the hypothesis that neostigmine when added to intrathecal bupivacaine could counteract the hypotensive effect of the local anaesthetic agents and thereby maintaining the stability of blood pressure and heart rate.
Patients and Methods: Sixty male adult patients,ASA 1-1 I requiring surgical procedures under subarachnoid block were randomly allocated into Neostigmine and Saline groups. Patients in Neostigmine group (NG) received 15mg of 0.5% hyperbaric bupivacaine, fentanyl 25mcg and preservative-free neostigmine 25mcg intrathecally while patients in the Saline group(SG) received same dose of heavy bupivacaine and fentanyl plus 0.5ml saline. Perioperatively, the haemodynamic (blood pressure and heart rate) changes after subarachnoid injection were recorded.
Results: Four patients (13.8%) in the saline group and two patients (6.7%) in the neostigmine group fulfilled the criteria for hypotension. The incidence of hypotension and bradycardia in the two groups was not statistically significant, p = 0.424 (hypotension) and p = 1.000 (bradycardia). Three patients (I 0.3%) in the saline group developed bradycardia, mean hear rate (MHR) of 51 beats/min while three patients ( 1 0.0%) in the Neostigmine group also had bradycardia, MHR of 54. beats/min, p = 0.166.
Conclusion: Neostigmine at a dose of 25mcg in combination with hyperbaric bupivacaine and fentanyl given intrathecally provided statistically insignificant haemodynamic stability in male patients that had surgical procedures under spinal anaesthesia.

Key Words: Intrathecal Neostigmine, Bupivacaine-Fentanyl, Haemodynamic changes, Spinal anaesthesia.